Hexadecyldimethyl benzyl ammonium bromide: an efficient catalyst for a clean one-pot synthesis of tetrahydrobenzopyran derivatives in water

A clean and efficient method for the synthesis of 2-amino-4-aryl-3-cyano-5-oxo-4H-5,6,7,8tetrahydrobenzopyran derivatives using hexadecyldimethylbenzyl ammonium bromide (HDMBAB) as the catalyst is described. This method provides several advantages, such as simple work-up procedure, environmentally benign, neutral conditions and high yields. In addition, water was chosen as a green solvent.